Exercise machine



FIG. 1 is a perspective view of the exercise machine;

FIG. 2 is a view from one side of the exercise machine;

FIG. 3 is a view from an opposing side of the exercise machine;

FIG. 4 is a top plan view of the exercise machine;

FIG. 5 is a bottom plan view of the exercise machine;

FIG. 6 is a front view of the exercise machine; and,

FIG. 7 is a rear view of the exercise machine.

The broken lines show environmental elements and form no part of the claimed design. 

The ornamental design for an exercise machine, as shown and described. 